1. Field of the Invention
The present invention relates to a balancing device for a suspended element, particularly for sash doors and windows to be vertically translated, comprising a shaft rotatably supported on a support, a pair of opposing pulleys attached to the shaft so as to be rotatable therewith, a pair of supporting ropes, one end of each of which being attached to the suspended element, and their respective other ends being attached to the pulleys, wherein each of the pulleys comprises a spiral groove onto which the respective ropes can be rolled for translating the suspended element.
The present innovation, in general, relates to a device for the balancing and the equilibration of the weight of suspended elements, particularly of doors of piece furniture and of sash windows and doors that can be vertically translated, to make their movement easier and their positioning in any point of their vertical travel balanced.
2. Description of the Related Art
The technique of providing pieces of furniture or fittings provided with sliding doors and sliding windows in particular to save space in houses and rooms of buildings, is well-known.
According to this known technique, in the pieces of furniture or fittings of the above mentioned type, the elements to be vertically translated are provided with pulleys and ropes linked to sash weights so as to balance the weight of the elements at issue, in order to allow their stable positioning in any point of their vertical travel.
However, it is clear that the presence of sash weights make the piece of furniture or the fittings heavier and increases their bulk because of the space required by the movement of the above mentioned weights.
A solution to these disadvantages has been proposed in the Italian patent application nr. PN. 92A000031 of the Applicant. The content thereof is incorporated herein by reference. Here, the sash weights have been replaced by traction springs that act on pulleys, each pulley having a side with a helical rim and a side with a spiral rim, on which the respective suspension ropes that link the element to the mentioned pulleys, wind up.
As a matter of fact, this prior art device reduces the weight of the element to be translated but it does not reduce its bulk, because the lateral thrusting spring needs space within the piece of furniture or window or door, thus even if the required space is reduced, it is not eliminated.
Moreover, maintaining the perfect and corresponding balancing of the thrusting springs is difficult to achieve with the passing of time, and causes sometimes unbalancings during the vertical travel of the moving element.